This is called "buying games based on potential." =D
Cuz all you've got is potential until games are in your hands. Reviews provide some education, maybe an aroma, but you don't get the real sandwich.
It's a good, fair thing anyway since it helps good ideas get a chance to be refined in sequel(s) by building a market/demand via initial sales. This is very important to games that lack BIG MARKETING hype machines.
If you're UNHAPPY with the game/direction in general, and wish the idea to sink & die, you come BACK HERE, MOUTH OFF on it, and not buy the sequel (or related titles). Business as usual.